The onset and/or severity of illness in mammals is related to the level of stress experienced by that mammal. In patients who are ill, either hypo- or hyperactivity of the hypothalamic-pituitary-adrenocortical (HPA) axis has been observed, which activity represents the physiological regulator of the stress response in mammals.
Regulation of HPA occurs via a multifaceted integrated mechanism, wherein corticotropin-releasing factor (CRF) and vasopressin (AVP) produced by the brain are believed to stimulate production of adrenocortico-tropin (ACTH) from the anterior pituitary, the primary inducer of cortisol secretion. Cortisol so produced has a negative influence upon ACTH secretion thus providing a feedback regulatory mechanism within this system.
An additional ACTH-inhibiting factor is postulated by Grossman and Tsagarakis (1989, J. Endocrinology, 123:169-172), which is termed corticotropin release inhibiting factor (CRIF or CIF), see Redei et al., In: Neuropeptides and Stress, Eds. Tache et al., Hans Selye Symposia on Neuroendocrinology and Stress, 1989, Springer-Verlag, N.Y.). This activity comprises an unidentified hypothalamic peptide, which peptide exhibits inhibitory activity on basal and CRF or stress stimulated ACTH secretion both in vitro and in vivo (Redei et al., 1984, In: Integrative Neurohormonal Mechanism Developments in Neuroscience, Vol. 16, Eds. Endroczi et a, Elsevier, Amsterdam).
A hypothalamic peptide fraction isolated from both pigs and rats was found to contain CRIF activity. When injected into rats, it suppressed corticosterone (CORT) response to footshock (Redei et al., 1984, In: Integrative Neurohormonal Mechanism Developments in Neuroscience, Vol. 16, Eds. Endroczi et al, Elsevier, Amsterdam). In addition, a peptide fraction (molecular weight 0.6-2.3 kDa) has been isolated from bovine hypothalamus which exhibits CRIF activity both in vitro and in vivo (Redei et al., In: Neuropeptides and Stress, Eds. Tache et al., Hans Selye Symposia on Neuroendocrinology and Stress, 1989, Springer-Verlag, N.Y.).
There has been a long felt need to determine the identity of CRIF because of its important relationship in regulating ACTH production. The present invention satisfies this need.
The invention relates to a substantially pure preparation of a CRIF peptide consisting of from three to twenty one contiguous amino acids contained within the amino acid sequence positioned between the fourth and fifth TRH sequence on a prepro-TRH protein.
In one aspect the peptide consists of a contiguous length of amino acids selected from the group consisting of three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty and twenty one amino acids.
In one embodiment, the peptide consists of four contiguous amino acids.
In another embodiment, the peptide has the sequence Leu-Met-Pro-Glu [SEQ ID NO:6].
In another embodiment, the peptide consists of nine contiguous amino acids.
In yet another embodiment, the peptide has the sequence Glu-Gly-Glu-Gly-Val-Leu-Met-Pro-Glu [SEQ ID NO:5].
In another aspect, the CRIF peptide is rat CRIF.
In one embodiment, the peptide consists of from three to twenty one contiguous amino acids of the sequence Phe-Ile-Asp-Pro-Glu-Leu-Gln-Arg-Ser-Trp-Glu-Glu-Lys-Glu-Gly-Glu-Gly-Val-Leu-Met-Pro-Glu [SEQ ID NO:1].
In another aspect, the CRIF peptide is mouse CRIF.
In one embodiment, the peptide consists of from three to twenty one contiguous amino acids of the sequence Phe-Ile-Asp-Pro-Glu-Leu-Gln-Arg-Ser-Trp-Glu-Glu-Thr-Glu-Gly-Glu-Glu-Gly-Gly-Leu-Met-Pro-Glu [SEQ ID NO:3].
In yet another aspect, the peptide is in a pharmaceutically acceptable carrier or diluent.
In a further aspect, the peptide further comprises the sequence pGlu-His-Pro-Gly-Arg-Arg [SEQ ID NO:4] at the amino terminal portion of the peptide.
In another aspect, there is provided a therapeutically effective amount of the peptide suspended in a pharmaceutically acceptable carrier.
Also included is a kit comprising a CRIF peptide and instructions for using the peptide.
The invention further includes a substantially pure preparation of a CRIF peptide consisting of from three to twenty five contiguous amino acids contained within the amino acid sequence positioned between the fourth and fifth TRH sequence on a prepro-TRH protein.
In one aspect, the peptide consists of a contiguous length of amino acids selected from the group consisting of three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, twenty one, twenty two, twenty three, twenty four, and twenty five amino acids.
In another aspect, CRIF peptide is human CRIF.
In one embodiment, the peptide consists of from three to twenty five contiguous amino acids of the sequence Leu-Ala-Asp-Pro Lys-Ala-Gln-Arg-Ser-Trp-Glu-Glu-Glu-Glu-Glu-Glu-Glu-Glu-Arg-Glu-Glu-Asp-Leu-Met-Pro-Glu [SEQ ID NO:2].
Also included is a therapeutically effective amount of a peptide consisting of from three to twenty five contiguous amino acids contained within the amino acid sequence positioned between the fourth and fifth TRH sequence on a prepro-TRH protein suspended in a pharmaceutically acceptable carrier.
Further included is a kit comprising a CRIF peptide consisting of from three to twenty five contiguous amino acids contained within the amino acid sequence positioned between the fourth and fifth TRH sequence on a prepro-TRH protein, and instructions for using the peptide.